;(function (doc, win, undefined) {
    var docEl = doc.documentElement,
      resizeEvt = 'orientationchange' in win? 'orientationchange' : 'resize',
      recalc = function () {
        var clientWidth = docEl.clientWidth;
        if (clientWidth === undefined) return;
        docEl.style.fontSize = 100 * (clientWidth / 375) + 'px';
      };
    if (doc.addEventListener === undefined) return;
    win.addEventListener(resizeEvt, recalc, false);
    doc.addEventListener('DOMContentLoaded', recalc, false)
  })(document, window);